Electric power-generating system



May 1, 1928. 1,668,285

J. POPE ELECTRIC POWER GENERATING SYSTEM Filed Jan. 1'7. 1923 Patented May 1, 192a laifi m UNITED STATES PATENT QFFIQ JOSEPH POPE, OF BROOKLINE, BIASSACH'USETTS, ASSIG-KOE TC STONE 5 WEBSTER, ING, OF BOSTON MASSACHUSETTS, A COBI?CRATION OF MASSACI-I'USETTS.

ELECTRIC PONER-G-ENEBIATING SYSTEM.

Application filed Januaiy 17, 1923. Serial No. 613,282

This invention relates to electric power means for supplying the auxiliary power- .generating systems of relatively large outconsuming devices of a steam turbo-generaput capacity and has particular reterence to tor power plant with power as economically (generating systems wherein steam turbines as that generated from the main turbo-genare utilized as the prime movers. erator and in as a reliable a manner as that 60 A steam turbine electric generating plant, supplied from a separate or auxiliary turboin addition to the steam boiler, turbine and generator unit, whereby to obtain a maxithe electric generator, which latter is directly mum of reliability and economy. coupled to the'steamturbine, has a number In carrying out my invention. I provide of auxiliary power consuming units, which a directly-coupled steam turbine and main 65 may toadvantage beuelect-rically operated, electric generator. The generator should ,'.which are: essential to maintain continuity have a capacity suflicient to meet the load of operation of the steam turbine unit; and requirements. The steam turbine should these auxiliary power consumingdevicesmay have a capacity sutiicient to operate the main include air pumps, water pumps. blowers generator under the load requirements and 7U and the like. In a large power plant, the to have an additional capacity great enough power required to operate the auxiliary deto supply the auxiliary power consuming devices may be considerable, although it may vices of the plant. An auxiliary electric be small compared to the output of the generator is directly-coupled to the common plant. For instance, apower plant deyelopshaft of the steam turbine and the main ing 30000 K. may require approximately generator, and said auxiliary generator is 2000K. W. to operate the auxiliary power arranged to supply the power necessary to y I consuming devices. -Heretotore, it has been operate the various auxiliary power consumcommon practice to supply electric power for ing devices. /Vith this arrangement. the

operating the auxiliary devices either trom auxiliary power is generated practically as 30 an auxiliaryturbo-generator unitor directly economically as the main power and is as from the main power bus of the station reliable as that supplied from an auxiliary through suitable transformingor converting turbo-generator unit for it is obvious that devices. The exhaust steam from the auxilauxiliary power will be available whenever 30 iary turbine commonly has been used for the main turbogenerator set-is in operation;

heating boiler feed water and. also. partially and disturbances the transmission or disexpanded steam extracted tromone or more tribution system connected with the main points .in the main turbine frequently has generator will have no ettect upon the supply been used for that purpose. of energy furnished by the auxiliary genera.-

It is highly desirable to maintain continutor. a0 ity of operation of the auxiliary devices as A further object is generally to improve the failure of one or more of said devices the construction and operation of electric may cause the entire plant to be shut down generating systems, by simplifying piping and. in thisrespect, the method of furnishsystems, and by providing means of obtain- 40 ing power to said auxiliary devices from the inn" auxiliary power not otherwise convenmain bus bar of the station is not desirable iently or satisfactorily obtained, when 0psince a disturbance upon the transmission crating steam pressure and temperatures are lines connected with said busmay effect .inhigh.

terruption of the current supply to the auxil- Other advantages appear from the speci 5 iary devices. It is well known that electrlfication and drawings. we

cal energy may be generated in a more eco- The figure is a diagrammatic representanomical manner with a large turbo-generator tion of the elements of an electric generating unit than with a small turbo-generator unit plant embodying my invention. and consequently, while auxiliary turbo- As here shown. have illustrated the powgenerator unit provides increased reliability er plant as comprising" two power generatof operation of the auxiliary devices, the exinp: units (although there may be more than pense of operation, at best, is substantially two units) which are adapted to be con- ;greatei than the expense of operating the denected through switches 10 to the main pow vices directly from the main power bus. bus, 1] from which various power transmit- An object of this invention is to provide ting lines 12 may extend. Both power gencrating units may be substantially indentical and for this reason, I have omitted, in one un t, certain pieces of apparatus wh1ch are illustrated in the other unit. Each power unit may comprise a main steam turbine 13 which is directly connected through the shaft 14. with the main electric generator 15, and said generator may be, and preferably is, a polyphase alternating current generator. of suitable capacity and characteristics. F or the purpose of example, said generator may have a capacity of 30,000 K. iv. and

deliver'a three-phase, sixty cycle current at 13,200 volts.v The steam turbine may be supplied with high pressure steam from the boiler 16 and the exhaust steam may be condensed in the condenser 17.

' Various auxiliary power consuming de vices are associated with the generating system. A pump 18 may be arranged to circu-, late a cooling medium through the condenser 17. A hot well pump 19 may be arranged to withdraw the condensed steam from the condenser and forceit through the preheaters 20 which may be heated by partially expanded steam from the main turbine in anv suitable manner not shown. A boiler feed pump 21 may withdraw the partially heated ivater from the preheaters 20 and force it through the economizer 22 into the boiler 16.

A fan or blower 23 may be associated with the furnace of the boiler 16 to supply air 7 for combustion. A direct current generator 30 is provided to excite the field of the main generator 15 and another generator 30 for exciting the field of the auxiliary generator 25. These may be driven by separate motors or by the same motor 30 which may receive its power through a suitable switch 31. There are also usually other auxiliary power consuming devices such as smaller fans, pumps, etc, which must be supplied with power for operation; and all of the auxiliary power-consuming devices are or may be operated by suitable electric motors.

In accordance, with this invention, I provide an auxiliary electric generator 25 for supplying the auxiliary devices with power and l couple said auxiliary generator directly to theshaft L1 of the main turbo-generator unit so that said auxiliary generator is driven directly by the main turbine 13. With this arrangen'ient, the auxiliary power is generated practically as economically as is themain power. The auxiliary generator be connected through a switch 26 with an auxiliary power bus 27 and is adapted to supply current thereto. The various auxiliary power consuming devices 18, 19, 21, etc, are or may be connected, through suitable switches 28 and transforming or converting devices 29, if necessary, to said auxiliary bus 27. This arrangement provides a reliability of operation-of the auxiliary power devices which can not be obtained when said'devices are supplied with energy from the main power bus and it also provides for an economy of operation of the auxiliary devices which can not be obtained when said devices are supplied with energy from a small auxiliary turbo-generator unit.

Preferably, the auxiliary buses 27 of the two or more turbo-generator units may be connected through suitable switches 32 to an auxiliary tie bus 33 whereby to permit the parallel operation of the auxiliary generators of each unit and from which through suitable leads 34 other devices may be supplied with energy. i V i I For supplying current to the various auxiliary devices of the powergenerating,units, whenv said generating units are being first set in operation, an auxiliary turbo-generator unitor. house turbine 35 may be provided which is adapted to be connected to the auxilia-rytie bus 38 through a suitableswitch 36 although, if the power plant has but one power generating unit, it may be connected instead to the auxiliary bus 27. Said house .turbine 35 may be provided with a small direct current generator 87 directly 7 connected theretofor the purpose of supplying exciting current to the fields of the alterexciter nating current generator. The generator should not be adapted tosupply current to any auxiliarydevices. After the main power generating units have been brought into operation, the house turbine may be shut down and disconnected from the auxiliary bus system.

If desired, the auxiliary bus system may be arranged for connection with the main bus 11 through suitabletransforming devices 40 and switchesetl so that upon occasion, the auxiliary power consuming devices may be operated supplementarily, from the main bus. It is for the purpose of permitting connection in this manner that the windings of the main and auxiliary generators are arranged to supply currents electrically in phase with each other. It is not intended that this connection be apermanent one,

but is to be used for short periods only, to

provide analternative method of starting the auxiliary devices of a generating unit which is to be placed in service. 7

Iclaim: j A power generating system comprising the combination of a steam turbine and main high-tension alternating current generator directly connected to the turbine shaft, a main high-tension power bus fed by said generator, asteam boiler arranged to supply steam to said turbine, auxiliary power-consuming devices essential to the generation of power associated with said system, an auxiliary low-tension power bus arranged to feed said auxiliary power consuming devices, means to supply power to said devices comprising an auxiliary low-tension alternating current generator directly connected mechanica-lly to the shaft of said turbine and arranged electrically in phase with said main high tension generator and connected with said auxiliary power bus, and supplemental means to feed said auxiliary power consuming devices comprising transforming devices connecting said main high-tension power bus and auxiliary low-tension power bus.

In testimony whereof, I have signed my 20 name to this specification.

JOSEPH POPE. 

